''Elysia marginata'' is a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

in the family

Plakobranchidae Plakobranchidae is a family (biology), family of sea slugs, marine (ocean), marine opisthobranch gastropod mollusks in the superfamily Plakobranchoidea. They superficially resemble nudibranchs but they are sacoglossans, members of the clade Sacog ...

. It is known for its ability to regenerate its whole body and heart after autotomizing it from its head.

Distribution

While there are few records of its distribution, ''E.marginata'' is widely distributed in the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

ocean region and has been found living in depths of . It was first observed off of the

Hawaiian Islands The Hawaiian Islands () are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the Pacific Ocean, North Pacific Ocean, extending some from the Hawaii (island), island of Hawaii in the south to nort ...

and

Tahiti Tahiti (; Tahitian language, Tahitian , ; ) is the largest island of the Windward Islands (Society Islands), Windward group of the Society Islands in French Polynesia, an overseas collectivity of France. It is located in the central part of t ...

Description

''E. marginata'' is described as having a green body with black and cream spots. It has tall, thin

parapodia In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; : parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed late ...

with a black band along its parapodial edge and a submarginal orange band. This species can be distinguished from other Indo-Pacific species by the white band found between the orange and black marginal bands. ''E. marginata'' has both a sedentary and migratory form, with the sedentary form reaching up to in length, and the migratory rarely exceeding .

Ecology

Like other species such as ''

Elysia ornata ''Elysia ornata'', commonly known as ornate elysia or ornate leaf slug, is a species of sea slug, a marine (ocean), marine gastropod mollusk. This sea slug superficially resembles a nudibranch, yet it does not belong to that suborder of gastropo ...

'', ''Elysia marginata'' lives in shallow water and feeds on

Bryopsis ''Bryopsis'', often referred to as hair algae, is a genus of marine green algae in the family Bryopsidaceae. Species in the genus are macroscopic, siphonous marine green algae that are made up of units of single tubular filaments. They can form ...

algae off the rocky bottom. E. marginata uses

kleptoplasty Kleptoplasty or kleptoplastidy is a process in symbiosis, symbiotic relationships whereby plastids, notably chloroplasts from algae, are sequestered by the host. The word is derived from ''Kleptes'' (κλέπτης) which is Greek language, Greek ...

to sequester the chloroplasts from the algae it consumes. These chloroplasts are stored in ''Elysia marginata'''s highly branched digestive gland that is lined by cells that maintain the ingested chloroplasts over its entire body. Unlike other sea slugs, which can only shed minor body parts, ''Elysia marginata'' and '' Elysia atroviridis'' can autotomize their heads completely from the rest of their body. ''E. marginata'' separates its head from the transverse groove over the course of several hours. Due to the slow nature of body separation, it is suggested that body shedding is a controlled mechanism to eliminate parasites, as the time-consuming nature of this behavior is not an efficient way to avoid predators and imitated predators in studies did not induce autotomy. However, like other

sacoglossa Sacoglossa are a superorder of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia known as sacoglossans. There are 284 valid species recognized within this superorder. Sacoglossans live by ingestin ...

ns, ''E. marginata'' can survive solely by photosynthesis from kleptoplasty after separation from their digestive system. Like other

sea slug Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod moll ...

Sacoglossa Sacoglossa are a superorder of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia known as sacoglossans. There are 284 valid species recognized within this superorder. Sacoglossans live by ingestin ...

ns are

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

s and reproduce sexually. They produce dimorphic eggs with two distinct larval morphs: small eggs that develop into

planktotrophic Marine larval ecology is the study of the factors influencing dispersing larvae, which many marine invertebrates and fishes have. Marine animals with a larva typically release many larvae into the water column, where the larvae develop before meta ...

larvae and large eggs that develop into lecithotrophic larvae that develop without needing to consume plankton.

References

Plakobranchidae Gastropods described in 1871 {{Gastropod-stub